Boris Johnson's preference for putting personality over messaging exposed him during a bruising interview on The Andrew Marr show, it has been claimed.

Yesterday the London Mayor was grilled by Andrew Marr's stand-in Eddie Mair over a range of incidents during his career.

Mair suggested Johnson was ‘a nasty piece of work’ after accusing him of 'making up quotes, lying to your party leader and wanting to be part of someone being assaulted'.

Despite some controversy over the nature of questions being put to Johnson, who repeatedly tried to steer the conversation to the present, Hanover director Gavin Megaw called the interview ‘fair game’.

Highlighting the fact that the fact that Johnson’s appearance came ahead of a documentary on the London Mayor, he said:

‘He was due a car crash interview because he always put his personality ahead of his messaging. This means he wouldn’t have been putting the hard work into why he was there, what he needed to say and what the pitfalls might be. It was an unusual interview in that it highlighted these deficiencies but it was always going to happen.’

Johnson, who said he disputed ‘all of those things’ suggested by Mair, admitted that he had ‘sandpapered’ quotes as a Times journalist.

In response to Mair suggesting he had lied to former Tory leader Michael Howard about an affair, Johnson said ‘he had never had any conversation’ with Howard and added that he ‘didn’t propose to go into all that again’.

He was also quizzed on a phone call aired during the documentary in which he was asked by friend Darius Guppy for the address of a journalist so, Mair claimed, ‘he can have him physically assaulted’.

The interview, which was branded #BorisNightMair on social media, came ahead of the airing of tonight’s Boris Johnson: The Irresistible Rise on BBC2.

Nick Laitner, director at MHP Communications, added: ‘Boris is such a unique political figure that he has managed to achieve real power and seniority without ever having to face any really tough questioning about his background, and he clearly never thought he would be put under such a harsh spotlight.

'Even so, it is frankly astonishing that he hadn’t put in even a modicum of preparation for some difficult questions about issues which have of course been in the public domain for years.’

The hour-long show was watched by an average of 1.7 million people on Sunday morning according to TV audience data.